1) Field of the Invention
The present invention relates to monitoring and recording the activity of a subject.
The present invention may be used in a variety of applications that require the assessment of an individual's daily activity in an unconstrained environment. Users of such an apparatus may include health practitioners, who can use the information provided by the device to determine a patient's compliance to a prescribed exercise routine and may further help the patient by motivating them to achieve set targets. Individuals can use the apparatus as a motivational aid to be more active, whilst the apparatus can also be used to provide a convenient means to measure and compare a subject's calorie expenditure with respect to their calorie intake. This device may be further utilized by Clinical Research Organizations who require tools that can provide data to demonstrate the efficacy of new drugs and medical interventions of clinical trials.
2) Description of Related Art
In the healthcare field any intervention associated with a mobility or co-morbidity factor can take advantage of the information given by the device. One such example of where this could be used is to address the issue of the growing evidence of type II diabetes, which can be linked to both obesity and inactivity. Furthermore achieving a general reduction in morbidity is important to the nation as increased ill health is expensive to treat, reduces the work force and decreases quality of life to those affected. This device provides a powerful tool for assessing the impact of mobility and sedentary lifestyles on health.
Devices that measure the activity of a person are well known in the art. Such devices include goniometers which allow continuous measurement of a joint angle, however, the data produced by a single goniometer cannot provide postural information and thus will not be able to assess between the different activities of the user. In addition goniometers are generally not used for long term recordings of unconstrained activities.
Other types of devices available are pedometers which count the number of steps taken in a given period of time and which are normally worn on the waist or ankle. The more sophisticated pedometers make a crude relationship between steps taken and calories used, however, are unable to discriminate between an upright and seated posture and do not record the rate of stepping, only the total number of steps.
Also available are actometers which utilize accelerometers to detect motion, these are similar to pedometers and can be worn on the wrist. These devices may include sophisticated algorithms that infer energy expenditure from the sensor output and most recently such devices have been mounted in the instep of footwear, with claims of the ability to measure the distance and speed of walking and running.
In addition, heart rate monitors are widely used to measure the intensity of exercise performed and while one such monitor presently exists with a calorie function, the calorie function only operates on elevated heart rates over 100 beats per minute, so only estimates the calories used during exercise.
None of the above mentioned devices can provide the data needed to evaluate a number of medical interventions, that is to say, provide results that indicate that the intervention has reduced the persons mobility handicap.